I think the moon that ponies talk about could refer to a moon cycle. A moon cycle refer to the moon cycling through the four phase: First Quarter, Full Moon, Last Quarter, and New Moon which last about 7 days each.

I'm not going to work on it right now but I have a new story idea title Martial Heart Tournament. It where the chaos goddess Kur-Sumer inform Rarity that Spike giving her the fireheart ruby is actually an ancient dragon bonding ceremony. So her choices is to either consummate the marriage, divorce Spike by destroying the fireheart ruby, or give it to the winner of the tournament for Spike's heart.

Here my Tatsurou-like story ideas inspire by Tatsurou and the web novel Everyone Else is a Returnee. In Everyone Else is a Returnee, the Earth is going into a higher plane of existence where magic become real. So God send various human to other worlds so they can level up and survive the new Earth. I called this Tatsurou-like MLP universe, the Fifth Great Catalysm, where Equestria is entering a higher plane so various being will sent to other worlds so they can survive.

Twilight Sparkle/Sandbar = the element of magic/leadership/sorceryMagic = an extraordinary power or influence from a supernatural source.Leadership = the ability to organized or guide others.Sorcery = the ability to influence fate or fortune.

Rarity/Smolder = the element of generosity/charity/beautyGenerosity = the quality of being kind and generous(unselfish)Charity = voluntary giving help to those in need.